Weather Blog: February Forecast

Thank you for stopping by the Weather Watch 12 Blog! February is the last month of Meteorological winter, then onto spring! Will February be more winter-like or will it resemble spring? To answer this question we use Lezak's Recurring Cycle, or the LRC to pinpoint when specific weather events will occur during February.

Weather Watch 12's most recent long range forecast based on the LRC for January included many successes, including predicting snow on January 30 a month in advance. The photo below from the U-Local section of WISN.com shows over 4" of snow in Aztalan in Jefferson County on January 30!

Before we breakdown the February forecast, let's go over the basics of the weather pattern theory(LRC) we use to make the forecast. We have been using the LRC in Milwaukee for the past several years with a great deal of accuracy and success to provide you forecasts weeks or months in advance.

A unique weather pattern sets up every year between the start of fall and mid-November.

Long term long-wave troughs(low pressure) and ridges(high pressure) become established. These dominant repeating features are clues to where storm systems will reach peak strength, and where they will be their weakest.

Once the weather pattern is set it cycles, repeats, and continues through winter, spring and into summer. Identifying the cycle length helps tremendously when making long range weather predictions.

The LRC is a 10-11 month pattern! There is a pattern! It is a sequence of troughs and ridges that are cycling around the Northern Hemisphere.

?Using the LRC and knowing the cycle duration is around 51-53 days in our current weather pattern(cycle duration was identified in late October), we can project forward highlighting potential active periods, dry stretches, and big temperature changes in the month ahead.

Here is a snapshot of what can be expected during an average February in Milwaukee.

Snowfall

9.8"

Temperatures

Average high: 1st 30 28th 37 -- Average low: 1st 16 28th 23

Below is the breakdown on the February forecast based on the LRC.

February 1-7

This period if basically covered in our 7 day forecast. So I will mention that back on December 31 when the January forecast was issued, the forecast included very cold temperatures to close January and hang around to start February -- potentially below zero. That is exactly what is still in the forecast to start February.

How was this cold snap identified over a month in advance? The key is looking back to previous cycles in our weather pattern, and looking at the 500mb(middle of the atmosphere charts). The current 500mb chart for January 31 is shown below. This map shows a large upper level low pressure area, or trough over the Midwest. This allows cold Canadian air at the surface to spill into the Midwest. Also of note on this map for comparison is the small upper low off the southern California coast.

Comparing the map above to 104 days ago, or two cycles prior shows the same upper level low over the Midwest and again notice the upper low off the southern California coast. This is the map comparison way to view similar parts of the LRC.

Frigid temperatures will ease slightly as clippers race by Feb 2-3 providing chances for snow showers or flurries with light snow accumulations possible. Another chance of primarily snow should return Feb 4-5(this was also mentioned weeks ago). As warmer air tries to flow north, a chance of a wintry mix or snow around February 7.

February 8-14

The second week of February represents possibly the best chance of seeing a major storm during the month in the Great Lakes or Midwest. If there is a 'signature' storm in the pattern, this is likely it.

Looking back to December this part of the pattern saw a large and intense upper level low slide near Chicago and then east into the Great Lakes. This resulted in a storm that dumped record rain and over 3" snow in Milwaukee. The storm produced a blizzard in parts of our viewing area! Below is the 500mb map from December 21, 2012. The feature of note is the low over the Great Lakes.

This time through the cycle the storm system/upper low should return around February 8-11. Rain, a mix, or snow is possible with windy conditions. This feature could develop into a major winter storm for parts of the Midwest, Great Lakes, or Ohio Valley. If you are hoping for a decent snow to enjoy some winter activities, this is the part of the pattern to watch closely.

As the storm exits a chunk of cold air will rush into southeastern Wisconsin that should last through Feb 12. Once this storm passes the 'wetter' or higher precipitation systems should ease as the active period ends for our area. Again the active period was defined as ~January 22 to February 12.

February 15-28

After a very busy first half of February, the weather should quiet down some to close the month.

The best snow chance the final 14 days of the month looks to occur Feb 17-19. While it may not snow all three days, one or two of these days should see precipitation. This period lines up with a trough that pushes into the Midwest most recently December 28-29. Fast forward 51-53 days and that lands around Feb 17-19.

The 500mb map below is from December 28, 2012 showing the trough or low pressure area in the Midwest and Plains. As the trough slides east a chance of precipitation will exist. This timeframe may also produce some lake effect snow.

A stronger cold front should arrive close to Feb 20-21 and deliver some chilly air. The final days of the month should be milder. Mild/warm weather should continue into the first week of March bringing above average temperatures to the area. Highs should peak with the warm-up around March 5-7 before a stronger cold front arrives.

TemperaturesNear Average -- Final average monthly temperature will depend on snowpack, if early February systems keep snow on the ground most days Feb 1-14, then temperatures will be a little cooler.

SnowfallNear Average(9.8") -- The snow forecast hinges greatly on precipitation type Feb 8-11. ~75% or more of the snow in February should occur during the first half of the month.

For the latest weather information watch WISN 12 News, or to ask a question regarding the LRC or February forecast tweet me @jnelsonweather